This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:    DTX Discontinuous transmission    eNB LTE Base Station    EPDCCH Enhanced Physical Downlink Control Channel    FDD Frequency Division Duplexing    HARQ Hybrid Automatic Repeat request    ISM band Industrial, Scientific and Medical Band    LAA Licensed-Assisted Access    LBT Listen Before Talk    LTE Long Term Evolution    MCS Modulation and Coding Scheme    MPR Maximum Power Reduction    NACK Negative ACK    PC Power Control    PCell Primary Cell    PDCCH Physical Downlink Control Channel    PHICH Physical HARQ ACK/NACK indicator channel    PRB Physical Resource Block    PUCCH Physical Uplink Control Channel    PUSCH Physical Uplink Shared Channel    RAN Radio Access Network    SCell Secondary Cell    SI Study Item    SINR Signal-to-Interference and Noise Ratio    SR Scheduling Request    SRS Sounding Reference Signal    TD TDD    TDD Time Division Duplexing    TL (Power) Threshold Level    TPC Transmission Power Control    TX Transmission    UCI Uplink Control Information    UE User Equipment    UL Uplink    Wi-Fi A trademark of Wi-Fi alliance
LTE offers higher data rates than prior released radio technologies. However, even though spectrum usage efficiency has improved, sometimes this alone cannot enable access data rates that may be required by some devices.
One method to achieve even higher data rates is to increase transmission bandwidths over those supported by a single carrier or channel is to use carrier aggregation (CA), or aggregation. Using carrier aggregation it is possible to utilize more than one carrier and in this way increase the overall transmission bandwidth.
Further, carrier usage for radio access technologies operations, such as LTE, in the unlicensed frequency spectrum can also increase the capacity of the operations. Each access point may support downlink and/or uplink communication for a number of user equipment (UEs) and vice versa.
The exemplary embodiments of the invention as discussed herein work to improve carrier selection for communications in an unlicensed band.